To increase the efficiency of refuse collection, many refuse collection companies use automated refuse loaders that lift a refuse container and then dump the refuse container into a refuse collection vehicle. Such automated refuse loaders can service a significantly higher number of customers in a given time period when compared with manually placing refuse into the refuse collection vehicle. This increased efficiency can result in substantially lower refuse collection costs. However, there are various challenges associated with the use of automated refuse loaders. For example, it is desired that the refuse loader mechanism operate as fast as possible to reduce cycle times and increase productivity.
Some refuse collection vehicles utilize an arm system that lifts the garbage container and then dumps the garbage container into a garbage truck. Such a mechanical arm systems may be mounted on the side of the garbage truck to permit garbage to be collected as the garbage truck is driving along a road. A garbage truck incorporating one such mechanical arm system is marketed by McNeilus under the designation STREETFORCE. Other types of arm systems may include front or rear loader systems that lift the garbage container from the front or the rear of the garbage truck.
In a common configuration, these mechanical arm systems include two primary components: a first arm portion that grasps the garbage container and a second arm portion that lifts the garbage container and dumps the garbage container into the garbage truck. However, other configurations are usable. Hydraulic actuators are generally used to provide for the motion of these mechanical arm systems. These hydraulic actuators are generally hydraulic cylinders, although there may be applications where hydraulic motors or other hydraulic rotary actuators are utilized.
Controls are generally provided within the operator's compartment of the refuse collection vehicle to allow the operator to control the motion of the arm system. In one typical arrangement, the hydraulic actuators are operated by a joystick that the operator moves when the operator intends to have the arm system move. The joysticks are each typically configured as pneumatic control valves, where a supply of pressurized air is supplied to the joysticks and movement of the joystick causes pressurized air to be transmitted through an appropriate channel of tubing. This pressurized air that is transmitted from the joystick is typically transmitted to a pneumatic actuator on a hydraulic control valve, where the air pressure acting on a piston or diaphragm causes a hydraulic control valve to move, which in turn causes pressurized hydraulic fluid to flow to the hydraulic actuator. This flow of pressurized hydraulic fluid causes the hydraulic actuator to operate. While the hydraulic system provides a high degree of reliability and relatively easy maintenance, there is typically a delay from when the pneumatic system is activated with the joystick until the hydraulic actuator is activated. Such delay reduces the productivity of the garbage collection process. Furthermore, this delay can reduce the tactile feel that the operator has for the operation of the mechanism.
Improved systems for controlling the motion of loader mechanisms on refuse collection vehicles are needed.